The objectives of this research are to demonstrate a new technique to solve the indeterminate problem of static joint force analysis and to apply this technique to the study of the forces about the elbow joint, one of the most neglected joints in biomechanics research. The components of the analysis consist of: 1) examine the EMG activities and calculate the tensions of all the elbow muscles during various elbow functions, 2) determine the forces on various articular surfaces of the elbow joint, 3) assess the function of various ligamentous restraints in the elbow joint. The methods of analyses include: 1) obtain detailed three-dimensional information of the functional anatomy of all the elbow muscles and ligaments through cross-sectional dissection and bi-planar x-ray investigations, 2) develop three-dimensional mathematical models of the elbow for the calculation of muscle forces, as well as joint contact and ligamentous forces during elbow functions, 3) perform in vitro ligamentous function test by examining the load through the joint under sequential cuts of surrounding ligaments, 4) verify the theoretical results by quantitative EMG analysis. The results of this study will provide detailed three-dimensional force distribution data which has up to now been unavailable. These data have far-reaching and immediate application to pressing clinical problems; including, how can the total elbow arthroplasty be improved to decrease loosening and what is required of the design to be in concert with the forces generated at the elbow? In addition, this information will explain the ever increasing athletic injuries to the elbow, as well as provide a rational basis for surgery and rehabilitation.